I'm lost !! Did you have pressure last season ?? ... or is this a new system being tested for the first time ? If this is a new system it may be a design problem but if it worked brfore it should work now ... A bad electric valve could be a reason you are not getting pressure ... very sneaky they do not open all the way sometimes or the solenoid is rusted and does not open and flow enough ... open the electric valve manually .. What happens ? .. make sure all your manual valves are all the way open ... Double Check. Any leaks or broken heads ?? Check carefully could be a broken nipple somewhere. "It's a bad design .Also the impact rotor is higher than the valve(i don't know if this is allowed)" Sounds like a goofy design to me ... the rotor should not factor in much ... in theory you can subtract about .5 psi per foot of elevation above your supply source source ... the hose connection is not a good idea .. What flow do you need and how long a run ? "The wire connection is connected with duct tape and it has been raining,the controller is not working for the valve ,so i tested it manually. " Sounds messy .. get some water tight connectors at your irrigation supplier. Check fuses .. Better yet design a better system ? Good Day ..

For most systems, capping off some sprinkler heads will make the operating water pressure higher. The right way to build a system is with a pressure regulator before the valves, but that can add almost $100 of cost so most people skip it. Without the regulator, pressure will depend on the flow. Most water mains exceed the recommended water pressure for sprinklers. Mine comes in at about 110 PSI. Sprinklers like to run around 40 or 25 PSI. The reason it usually works is there are so many heads on a zone that the valve restricts the flow and brings the pressure down. When you cap off some heads, the pressure goes up. Many valves have a flow control option and if yours does, you can adjust it to bring the pressure back down to the optimal level. If your valve does not have flow control, you can implement your own with a gate valve in series with your sprinkler valve.

To northga, I found this post purely by accident. I thought I would give my 2 cents worth anyway. Do not bother with a larger hose ( if you need a new hose anyway by all means get the 3/4". Don't bother with the expense of a 1" ). The increase in pressure will be negligable ( unless you have a long run of hose ). Someone answered your post and part of his information stated that in your area it was common to have a 3/4 inch service line and water meter. If true your water venders' engineers need an education, 3/4 inch is absurd unless you are providing water supply to a camper. In any case it sounds like a plumbing problem ( very common ). Many times ( frankly most of the time ) pipe and fitting sizes are just to small ( even if 'up to code' )and create velocities that are to high, thus a more than reasonable pressure drop. I would love to sell you a booster pump, but that will not solve the problem ( considering the information you have provided). The first thing to due is to confirm the size of your service line and water meter ( if 3/4" you are out of luck ). Your water vender should be able to provide you this information. Second, locate your water meter. There will be some type of isolation valve(s)( shut-off valve(s) ). Be sure the valves are fully open ( you would be surprised how often they are not ). Next locate your pressure regulating valve ( yes you do have one ), if there are isolation valves here as well be sure they are fully open. I'm sure you have the same[pressure]problem inside the home when several demands are made on the supply ( this occurs in most every home due to small pipe sizes ).[ If the plumbing were sized and piped correctly your shower would not be affected by a toilet flushing. ] I am getting long here... A booster pump ( or any increase in pressure ) will not by itself provide an increase in flow ( gpm ). Flow is determined by what the plumbing (size) can provide within acceptable losses and by the demand on said plumbing. If you are demanding 20 gpm ( sprinklers, showers, dishwasher, etc ) all at the same time and your plumbing can only provide 12 gpm ( at 5 feet per second velocity ) you will give up the pressure that's available. There are many things you can do, even if your water meter is to small ( including but not limited to installing a booster pump ), however any "fixes" will result in increased flow and pressure for the sprinkler(s) and reduced flow and pressure in the home ( all things being equal ), short of installing a second service line and water meter. If there is a hose bib available upstream ( prior to ) of entering the house then do use this connection ( see "fixes" above ), this alone may provide you with the what [pressure] you are looking for. The bottom line is consider doing your outside watering during a time when houshold water consumption is not an issue. Hell, I've got to get back to work hope this has been some help. MChristensen, Technical Consultant Booster Pump Tech Here is a link that might be useful: GardenWeb

You can flush the head by removing the nozzle and turning the zone on for a few seconds. If water comes shooting out, then the blockage is either gone or was never the problem. Also, check the filter under the nozzle for debris.